Furniture drive

ABSTRACT

The invention relates to a furniture drive with a drive unit having an electric motor, a pull-out guide for drawers, a chassis track, a middle track and a drawer track. The middle track and the drawer track are mechanically interconnected and forcibly controlled. The drive unit drives the middle track.

The present invention concerns a furniture drive comprising a drive unit having an electric motor, and a drawer extension guide comprising a body rail, a central rail and a drawer rail, wherein the central rail and the drawer rail are mechanically positively controlled in relation to each other.

A furniture drive of that kind is to be found for example in EP 1 323 363 A1. The furniture drive shown there has the problem of being relatively large in structure. They are therefore generally fixed on the rear side of the furniture body or carcass between the two drawer extension guides. For various reasons however it would be desirable to afford a furniture drive which is of such a compact structure that it can be fixed directly to a drawer extension guide. In that case for example the drawer extension guide and the furniture drive could be fitted in a structural unit, in one working step. Apart from that the space in the region of the rear side of the furniture body between the drawer extension guides would remain free.

The object of the invention is to provide such a furniture drive having the features of the classifying portion of claim 1.

That object is attained by a furniture drive having the features of claim 1.

The measure defined in claim 1 provides that the furniture drive has to be active only over half the opening travel of a drawer fixed to the drawer rail. That permits the furniture drive to be of an extremely compact structure.

Further advantageous configurations of the invention are set forth in the appendant claims.

Further advantages and details will be apparent from the Figures and the specific description relating thereto. In the Figures:

FIGS. 1 a and 1 b show perspective views of an embodiment of a drive unit of a furniture drive according to the invention, with a cover fitted and removed respectively,

FIG. 2 shows an exploded view of a drive unit as illustrated in FIGS. 1 a and 1 b,

FIG. 3 shows a diagrammatic view of a drawer extension guide showing the configuration of the drive train between the cable pulley and the drawer rail,

FIGS. 4 a and 4 b show a perspective view and a detail view of an embodiment of a drawer extension guide with furniture drive fixed thereto,

FIGS. 5 a and 5 b show a front view of the drawer extension guide shown in FIGS. 4 a and 4 b and a detail view thereof,

FIGS. 6 a through 6 c show a further perspective view and two detail views of the FIGS. 4 and 5 structure, and

FIGS. 7 a and 7 b show a further perspective view and a detail view of the FIGS. 4 and 5 structure.

It is to be presupposed that both opening and also closing of the movable furniture part (for example a flap of an article of furniture or a drawer) is possible with the furniture drive according to the invention. In the illustrated embodiment that is achieved by a reversible electric motor.

FIG. 1 a clearly shows the compact structure of a drive unit 1 of a furniture drive according to the invention, wherein FIG. 1 a shows at the left the housing of an electric motor 2 and at bottom right a part of the drive output shaft 4 which extends parallel to the housing of the electric motor 2 and laterally therebeside. The drive shaft 3 of the electric motor 2 which cannot be seen in FIG 1 a itself extends along a notional axis 3′. The drive output shaft 4 extends along a notional axis 4′. In this embodiment it is provided that the notional axes 3′, 4′ and therewith the drive shaft 3 and the drive output shaft 4 extend in laterally displaced and mutually parallel relationship.

In FIG. 1 b the housing 12 has been removed to allow a view of the transmission 5. The precise structure of the drive unit 1 will be described with reference to the exploded view in FIG. 2.

The drive train begins with the electric motor 2 having a drive shaft 3. The drive shaft 3 is connected to one side of a dog clutch 14 which has a sound decoupling means. The other side of the dog clutch 14 is connected to a worm 15. The illustrated gears 16 through 19 form a step-down assembly 6 of the transmission 5. In this case the worm 15 meshes with the gear 16 which is mounted on the shaft 20, being connected non-rotatably to the gear 17. The shaft 20 is in turn mounted between the housing portions 21, 22. The gear 17 meshes with the gear 18 which in turn engages into the gear 19. It is to be noted that the rotary movement of the worm 15, which takes place about a vertical axis, is converted by way of the gears 16 through 18 into a rotary movement about a horizontal axis, in which case the gear 19 again performs a rotary movement about a vertical axis and that vertical axis extends in laterally displaced and parallel relationship with the original vertical axis. The gear 18 is also mounted between the housing portions 21, 22 by way of a shaft 23. Arranged between the gear 19 and a further housing portion 24 is a spacer 25 in the form of a sleeve. Downstream of the step-down assembly 6 arranged in the drive train is an overload clutch 7 formed by a thrust bearing 27 and the component 28 as well as a freewheel clutch 8 which can be braked by a brake 29. In that case the transmission 6 co-operates with the clutch 7 by way of a drive output 26. The drive output shaft 4 is fixed to the freewheel clutch 8. Fixed to the drive output shaft 4 is the cable pulley 30 of a cable line assembly 9 (not shown in FIG. 2), by way of which pulley the drive force is passed on to the furniture drive 1.

FIG. 3 diagrammatically shows the further configuration of the drive train, showing a body or carcass rail 10 to be fixed to the furniture body or carcass, a central rail 11 and a drawer rail 12 to be connected to a drawer. The central rail 11 and the drawer rail 12 are connected together in known manner by a positive or forced control so that a movement of the central rail 11 results in a corresponding movement of the drawer rail 12. In that case the positive control arrangement includes a cable line assembly 32 extending between two pulleys 31, an entrainment member 33 being fixedly connected to the cable line assembly 32. The entrainment member 33 couples to the drawer rail 12 by way of a coupling 34. A further entrainment member 42 is fixedly connected to the cable line assembly 32. That entrainment member 42 is in turn fixedly connected to the body rail 10 by way of a tongue 43 (see FIG. 7 b).

The drive for the central rail 11 goes by way of an entrainment member 35 which is fixedly connected thereto and which moreover is fixedly connected to a cable line assembly 9, the cable line assembly 9 being drivable by the cable pulley 30. In this case the cable line assembly 9 further goes by way of a direction-changing pulley 36 which does not have any driving function.

The drive force of the drive unit 1 therefore passes from the drive output shaft 4 by way of the cable pulley 30 and the cable line assembly 9 to the entrainment member 35 and thus the central rail 11. The central rail 11 is thereby moved forwards and backwards parallel to the stationary body rail 11, depending on the direction of movement of the cable line assembly 9. That movement of the central rail 11 is transmitted by way of the positive control (components 31 through 34, 42 and 43) to the drawer rail 12 and thus to the drawer (not shown in FIG. 3) connected to the drawer rail 12. The drawer can therefore be reciprocatingly displaced as desired by the furniture drive 1 between a completely closed position in the furniture body and a completely open position.

FIGS. 4 a and 4 b show two travel measuring devices which on the one hand comprise the potentiometer 37 and the control member 38 and on the other hand the potentiometer 39 and the gear mechanism 40. The signals of those travel measuring devices can be fed to a control or regulating device (not shown) for the furniture drive, wherein control or regulation of the furniture drive can be effected in dependence on those signals. In particular it is possible to implement a touch-latch function, that is to say the control or regulating device activates the drive unit 1 of the furniture drive as soon as a displacement, caused by a user, of the furniture part (here the drawer) is detected by way of one of the travel measuring devices.

The control member 38 of the first travel measuring device is connected in this case to the central rail 11 by way of the component 41 and can thus determine the position of the central rail 11. As the drawer rail 12 is connected to the central rail 11 by way of the positive control assembly, the position of the drawer rail 12 can also be indirectly determined. That can be used for a touch-latch functionality in relation to opening of the drawer. After a predetermined distance the control member 38 and the component 4 separate.

The second travel measuring device is available for a touch-latch functionality in respect of closure. The potentiometer 39 of the second travel measuring device is connected to the drive output shaft 4 by way of the gear mechanism 40 and can also determine the position of the drawer rail 12.

FIGS. 5 a and 5 b show views from the front of the drawer extension guide.

FIGS. 6 a through 6 c show the drawer rail 12 in the partially extended condition (approximately the central position). That provides that the central rail 11 can also be partially seen. It is possible in particular to see a direction-changing pulley 31 (see FIG. 3) as well as the cable line assembly 32 of the positive control arrangement.

Furthermore the direction-changing pulley 36 which is fixed to the body rail 10 as well as the cable line assembly 9 can be seen in FIG. 6 b on the left-hand side.

FIGS. 7 a through 7 b show the drawer extension guide with the drawer rail 12 fully retracted and the central rail 11 fully retracted. It is possible to see in particular in FIG. 7 b the other direction-changing pulley 31 of the positive control arrangement. It is further possible to see the arrangement of the entrainment member 42 on the tongue 43 connected to the body rail 10. 

1. A furniture drive comprising: a drive unit having an electric motor, and a drawer extension guide comprising a body rail, a central rail and a drawer rail, wherein the central rail and the drawer rail are mechanically positively controlled in relation to each other, wherein the drive unit drives the central rail.
 2. A furniture drive as set forth in claim 1 wherein the electric motor has a drive shaft coupled to a drive output shaft of the drive unit, wherein the drive output shaft is arranged extending at least approximately parallel to the drive shaft laterally beside the electric motor.
 3. A furniture drive as set forth in claim 1 wherein the drive unit has a transmission, the transmission having a step-down means and/or an overload clutch and/or a freewheel clutch.
 4. A furniture drive as set forth in claim 1 wherein the drive unit is constantly connected to the central rail.
 5. A furniture drive as set forth in claim 4 wherein the drive unit is coupled to the central rail by way of a cable line assembly.
 6. A furniture drive as set forth in claim 2 wherein the electric motor, optionally the transmission and the drive shaft are so arranged that the longitudinal extent of the drive unit is given substantially by the longitudinal extent of the electric motor. 